Together with the higher proportions of Th2/1 hybrid cells counteracting type 2 responses in C57BL/6 mice in an IFN-γ dependent manner, the limited stress experienced during larval and early adult development due to modest recruitment of adaptive and innate type 2 cells likely benefits parasite fitness at later stages of infection, resulting in the more long-lived infection and higher egg deposition in this mouse line. This evidence concerns the gene IFNG and infection.